Optical fiber has been widely used as a transmission medium for signals in recent years. A fiber optic connector and a fiber optic adapter can be used if two optical fibers are required to be connected with each other. In general, the fiber optic connectors are disposed at the two ends of the fiber and can be inserted into the opening of the fiber optic adapter. The fiber optic adapter has two openings, and each opening is connected with one fiber optic connector. In order to transmit the signal to a greater distance, the energy coupled to optical fiber is increased greatly. When a high-intensity infrared beam is emitted from one end of the fiber, permanent damage to the vision of a user is often caused if the user's eyes are inadvertently exposed directly to the beam.
U.S. Pat. No. 9,618,715 discloses a fiber optic adapter having a light-shielding member. In addition to shielding a high-intensity infrared beam, the light-shielding member can also be used to prevent dust from entering the optical fiber adapter to solve the dust-proof problem. However, the light-shielding member cannot be applied to a fiber optic adapter with a hook, and therefore it is not practical.